‌The NHS advises that nine key groups to tell a doctor before taking amitriptyline to avoid various negative side effects. This helps your symptoms if you're taking amitriptyline for pain relief or migraine." Anyone already prescribed a different medication is therefore urged to consult a doctor or pharmacist before also taking amitriptyline. Some antidepressants can also affect the way amitriptyline works, and in some cases cause very high blood pressure. The NHS also adds: "Some people feel sleepy and dizzy while they're taking amitriptyline.